Some advocate the 'Instructor Licence' - I do not.
However, I do support a return to the old 'PPL/FI' type rating and there is work going on behind the scenes to achieve this at some stage in the future. Many in the industry would be glad to have more part-time PPL/FIs whose experience and teaching skills would probably be higher than many low-time hours builders with their shiny new CPLs.
There is a need for a mix of both; however, currently the 'part-timers' are more or less restricted to CRI(SPA) instruction - for which they cannot be paid on a PPL - unless they do all those exams about how many megaphones are needed on a 747 or how wide the stripes have to be on the streamers flown beneath tethered kites.....
But if you want to be paid for instructing without needing a CPL, you would have to convince the BMAA of your worth!